1. Field of the Invention
The present invention relates to a route guidance system, which searches a guidance route to a destination and provides voice guidance of respective guidance landmarks located in the guidance route.
2. Description of Related Art
One exemplary prior art system, which sets a guidance route based on context of a voice command of a user, is a navigation system recited in Japanese Unexamined Patent Publication No. 2002-107167.
In the prior art system, the context of voice command of the user is divided into a plurality of simple sentences based on a preset syntax, and a destination is set by analyzing the context of each divided simple sentence, More specifically, when the user speaks “set a third building, which is located on a right side of a road encountered right after passing straight through the Yokohama station's west exit, as a destination”, this voice command is divided into two simple sentences, i.e., the sentence of “passing straight through the Yokohama station's west exit” and the sentence of “setting the third building, which is located on the right side of the road, as the destination”. Next, the Yokohama station's west exit is searched and is identified from map data based on the sentence of “passing straight through the Yokohama station's west exit”, and the road, which passes straight through the Yokohama station's west exit, is searched and is identified. Finally, the third building, which is located on the right side of the searched road that passes straight through the Yokohama station's west exit, is searched and is identified. This building is set as the destination, and the corresponding navigation is performed.
As described above, in the prior art system, the destination and the guidance route is set when the geographical information around the destination is inputted to the system through the voice of the user. However, when the user is not familiar with the geographical information around the destination, for example, at the time of visiting the destination first time, the user cannot set the destination and the guidance route through his/her voice. Besides the above system, another route guidance system is known. This route guidance system searches and notifies a guidance route to a destination, which is manually set by a user based on map information, according to, for example, a Dijkstra method. However, even in this route guidance system, it is difficult to set a user's intended guidance route.